1. Field of the Invention
This invention relates to a junction socket applied to an electrical junction box for connecting wire harnesses to each other and the like. This junction socket is used for connecting a male terminal projecting from an end of a bus bar to a male terminal extended from an electronic component.
2. Description of the Related Art
Generally, a case of an electrical junction box, such as a fuse box, a relay box, a junction box, accommodates bus-bar-circuit boards, and they are stacked if necessary. Each of these bus-bar-circuit boards is configured with a plurality of bus bars and an insulating circuit board for supporting these bus bars. A fuse mounting block, a relay mounting block, and a connector mounting block for connecting a wire harness, are provided on an outer surface of the case. A male tab (flat) terminal is formed projectingly from the bus bar. Male tab terminals are extended from electronic components such as the fuse or the relay. These male terminals of the bus bars and the electronic components are formed opposite to each other and connected to each other via the junction socket.
An embodiment of a conventional junction socket is shown in FIG. 7 and disclosed in Japanese Patent Application Document Laid-Open No. 2002-78153 (Page 3 to 4, FIG. 2). According to this embodiment, the junction sockets are easily mounted on the electrical junction box, and assembling workability of the electrical junction box is improved. The electrical junction box (not shown) includes a circuit board having bus-bars; an upper cover to cover an upper surface of the circuit board, on which electronic components such as a relay or a fuse are mounted; and a lower cover to cover a lower surface of the circuit board. A junction socket 50 for connecting a male terminal 57 formed on an end of the bus bar to a male terminal 58 extended from the electronic component is temporarily locked in a terminal receiving part with a terminal locking member. Then, the upper cover covers the circuit board to connect the junction socket 50 to the male terminal 57 of the bus bar.
Stamping and bending a conductive substrate forms the junction socket 50. This junction socket 50 includes a receptacle 51 having openings at both ends, and a resilient contact piece 53 formed integrally with the receptacle 51.
The resilient contact piece 53 includes a first terminal contact convex 53a, which is extended from a front wall 51a of the receptacle 51 and bent inward, and a second terminal contact convex 53b, which is formed by further bending a front end of the first terminal contact convex 53a. 
The male terminal 58 of the electronic component is inserted from a top opening 55 of the receptacle 51 and held between a rear wall 51b and the first terminal contact convex 53a. The male terminal 57 of the bus bar is inserted from a bottom opening 56 of the receptacle 51 and held between the second terminal contact convex 53b and a front wall 51a. 
However, there are problems as follows to be solved in this conventional junction socket. Both of male terminals 57, 58 have face to face contact with front and rear walls 51a, 51b of the receptacle 50 respectively. Therefore, as shown in FIG. 8, when the male terminals 57, 58 are inserted obliquely, contact positions on the walls 51a, 51b are shifted, so that the male terminals 57, 58 no longer have face to face contact with the walls 51a, 51b. Further, contacting parts of walls 51a, 51b no longer face to terminal contact convexes 53a, 53b respectively via male terminals 57, 58. Therefore, distal ends of male terminals 57, 58 may be deformed by bending moment, or the resilient contact piece may be pried by the male terminals 57, 58 to be plastically deformed.
Further, when a base side of the resilient contact piece 53 having a curve shape is pried by the male terminals 57, 58, the resilient contact piece 53 may be turned into a crushed shape. Therefore, contact pressure between the male terminals 57, 58 and terminal contact convexes 53a, 53b may decrease to reduce contact stability. Further, when the resilient contact piece 53 is crushed, resiliency of the resilient contact piece 53 may be weakened. This also may reduce contact stability.
These problems can be solved to some extent by managing precisely sizes of the male terminal 57 of the bus bar and the male terminal 58 of the electronic component. However, this cannot solve the problem perfectly. Further, managing precisely sizes of those including a plurality of small electronic components in the electrical junction box makes another problems such as increasing electronic components cost, or reducing assembling workability. Thus, there are demands for a junction socket that can easily compensate for dimensional errors of the male terminals 57, 58 and for assembling errors without managing sizes of the male terminals 57, 58 precisely to improve the contact stability.
For resolving the problems described above, an object of this invention is to provide a junction socket, which prevents a resilient contact piece from being deformed by prying when inserting a male terminal; guarantees stable contact pressure between the terminals; and thereby improves contact stability between the terminals.